From: paladz <453256728@qq.com>
Date: Tue, 10 Oct 2017 02:04:05 +0000 (+0800)
Subject: init version for enable mining diff calculate func
X-Git-Tag: v1.0.5~466^2~3^2~1
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=7b2cd807874480986d2fd0ff3f9ab3ece990a576;p=bytom%2Fbytom.git

init version for enable mining diff calculate func
---

diff --git a/consensus/difficulty.go b/consensus/difficulty.go
index f1e2b5fb..86e21fda 100644
--- a/consensus/difficulty.go
+++ b/consensus/difficulty.go
@@ -82,26 +82,21 @@ func BigToCompact(n *big.Int) uint64 {
 }
 
 func CheckProofOfWork(hash *bc.Hash, bits uint64) bool {
-	if HashToBig(hash).Cmp(CompactToBig(bits)) <= 0 {
-		return true
-	}
-	return false
+	return HashToBig(hash).Cmp(CompactToBig(bits)) <= 0
 }
 
-func CalcNextRequiredDifficulty(lastBH, prevBH *legacy.BlockHeader) uint64 {
-	return uint64(2161727821138738707)
-
-	//TODO: test it and enable it
+func CalcNextRequiredDifficulty(lastBH, compareBH *legacy.BlockHeader) uint64 {
 	if lastBH == nil {
 		return powMinBits
-	} else if (lastBH.Height+1)%blocksPerRetarget != 0 {
+	} else if (lastBH.Height+1)%BlocksPerRetarget != 0 {
 		return lastBH.Bits
 	}
 
-	actualTimespan := int64(lastBH.Time().Sub(prevBH.Time()).Seconds())
+	targetTimeSpan := int64(BlocksPerRetarget * targetSecondsPerBlock)
+	actualTimespan := int64(lastBH.Time().Sub(compareBH.Time()).Seconds())
+
 	oldTarget := CompactToBig(lastBH.Bits)
 	newTarget := new(big.Int).Mul(oldTarget, big.NewInt(actualTimespan))
-	targetTimeSpan := int64(blocksPerRetarget * targetSecondsPerBlock)
 	newTarget.Div(newTarget, big.NewInt(targetTimeSpan))
 	newTargetBits := BigToCompact(newTarget)
 
diff --git a/consensus/difficulty_test.go b/consensus/difficulty_test.go
new file mode 100644
index 00000000..ea5dbd6a
--- /dev/null
+++ b/consensus/difficulty_test.go
@@ -0,0 +1,41 @@
+package consensus
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/bytom/protocol/bc/legacy"
+)
+
+func TestCalcNextRequiredDifficulty(t *testing.T) {
+	targetTimeSpan := uint64(BlocksPerRetarget * targetSecondsPerBlock * 1000)
+	cases := []struct {
+		lastBH    *legacy.BlockHeader
+		compareBH *legacy.BlockHeader
+		want      uint64
+	}{
+		{nil, nil, powMinBits},
+		{&legacy.BlockHeader{Height: BlocksPerRetarget, Bits: 87654321}, nil, 87654321},
+		{
+			&legacy.BlockHeader{Height: BlocksPerRetarget - 1, TimestampMS: targetTimeSpan, Bits: BigToCompact(big.NewInt(1000))},
+			&legacy.BlockHeader{Height: 0, TimestampMS: 0},
+			BigToCompact(big.NewInt(1000)),
+		},
+		{
+			&legacy.BlockHeader{Height: BlocksPerRetarget - 1, TimestampMS: targetTimeSpan * 2, Bits: BigToCompact(big.NewInt(1000))},
+			&legacy.BlockHeader{Height: 0, TimestampMS: 0},
+			BigToCompact(big.NewInt(2000)),
+		},
+		{
+			&legacy.BlockHeader{Height: BlocksPerRetarget - 1, TimestampMS: targetTimeSpan / 2, Bits: BigToCompact(big.NewInt(1000))},
+			&legacy.BlockHeader{Height: 0, TimestampMS: 0},
+			BigToCompact(big.NewInt(500)),
+		},
+	}
+
+	for i, c := range cases {
+		if got := CalcNextRequiredDifficulty(c.lastBH, c.compareBH); got != c.want {
+			t.Errorf("Compile(%d) = %d want %d", i, got, c.want)
+		}
+	}
+}
diff --git a/consensus/general.go b/consensus/general.go
index 5362e607..c694fb05 100644
--- a/consensus/general.go
+++ b/consensus/general.go
@@ -16,7 +16,7 @@ const (
 
 	// config for pow mining
 	powMinBits            = uint64(2161727821138738707)
-	blocksPerRetarget     = uint64(1024)
+	BlocksPerRetarget     = uint64(1024)
 	targetSecondsPerBlock = uint64(60)
 )
 
diff --git a/consensus/general_test.go b/consensus/general_test.go
index 94089514..dc861c8a 100644
--- a/consensus/general_test.go
+++ b/consensus/general_test.go
@@ -1,18 +1,5 @@
 package consensus
 
-import (
-	"fmt"
-	"math/big"
-	"testing"
-)
-
-func TestCalcNextRequiredDifficulty(t *testing.T) {
-	//fmt.Println(CalcNextRequiredDifficulty())
-	x := big.NewInt(123)
-	y, _ := x.SetString("94847123945178081620347972471576132812524935594538618173381454864040345", 10)
-	fmt.Println(BigToCompact(y))
-}
-
 /*func TestSubsidy(t *testing.T) {
 	cases := []struct {
 		bh      *BlockHeader
diff --git a/mining/mining.go b/mining/mining.go
index 610b3f3c..ecf0a3fa 100644
--- a/mining/mining.go
+++ b/mining/mining.go
@@ -64,6 +64,11 @@ func NewBlockTemplate(c *protocol.Chain, txPool *protocol.TxPool, addr []byte) (
 	blockWeight := uint64(0)
 	txFee := uint64(0)
 
+	var compareDiffBH *legacy.BlockHeader
+	if compareDiffBlock, err := c.GetBlock(nextBlockHeight - consensus.BlocksPerRetarget); err == nil {
+		compareDiffBH = &compareDiffBlock.BlockHeader
+	}
+
 	b := &legacy.Block{
 		BlockHeader: legacy.BlockHeader{
 			Version:           1,
@@ -71,7 +76,7 @@ func NewBlockTemplate(c *protocol.Chain, txPool *protocol.TxPool, addr []byte) (
 			PreviousBlockHash: preBlock.Hash(),
 			TimestampMS:       bc.Millis(time.Now()),
 			BlockCommitment:   legacy.BlockCommitment{},
-			Bits:              consensus.CalcNextRequiredDifficulty(nil, nil),
+			Bits:              consensus.CalcNextRequiredDifficulty(&preBlock.BlockHeader, compareDiffBH),
 		},
 		Transactions: make([]*legacy.Tx, 0, len(txDescs)),
 	}